Types of Aquaculture and Recent Advances toward Farming

 

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Types of aquaculture and recent advances toward farming 

Fisheries and Aquaculture knowledge. 

 

Highlighted points

 

Types of aquaculture systems pdf

 

Types of aquaculture systems ppt

 

Types of aquaculture pdf

 

Intensive aquaculture system

 

Types of fish culture system

 

Methods of aquaculture

 

Types of ponds for fish

 

 

Aquaculture

 

Aquaculture refers to the cultivation/ rearing/raising of aquatic organisms for commercial, recreational or public purpose. Due to diversification of aquaculture operations, the description of various types of aquaculture systems may be intricate and puzzled too.

 Mostly aquaculture systems are classification on the basis of below four criteria:

 

a)  Types of rearing facilities  (ponds, cages, raceways, pens, enclosure, tank)

b)  Water exchange (static, open and closed).

c)   Intensity of culture (extensive, semi-intensive, intensive).

d)  Fish farming methods (monoculture and polyculture).

A) Types of rearing facilities 

1.      Ponds

Ponds are commonly used for fish culture. In ponds water is maintained in enclosed area by construction of dike or bund, where aquatic organisms are stocked and grown. Rainwater, canal water and manmade bore are mostly used to fill the ponds. Ponds differs widely in size, shape, topography, water and soil quality. 

Different types of ponds are as:

1.     Spawning ponds

2.     Fry nursing ponds

3.     Fry holding ponds

4.     Storage ponds for marketable fish

5.     Overwintering ponds

2.      Raceways

Raceway culture is simply rearing and raising of fish in running water. Water flows at fast rates so the residence time of water in a raceway is very short usually on the order of a few minutes instead of hours or days in ponds. Fishes are stocked in high density in raceways so referred as high production system. Raceways ponds are of two types.

Linear type: Ponds are arranged in sequence. In this system the volume of water entering the pond is large and same water is used again and again from pond to pond. The main drawback of this system is that if disease occurs in initial ponds that may directly affect the connected ponds.

Lateral type: Ponds are arranged in parallel .In this type the volume of water entering the pond is small but fresh supply of water is always guaranteed. No transfer of disease occur from pond to pond

 

3.       Concrete or fiberglass tanks

Various types of tanks are available. Based on the shapes the tanks are circular, rectangular or oval. That water enters through nozzles in such a way that creates a rotary circulation within the tank and discharge occur through tank center by bottom drain surrounded by screen. Typically circular tanks is 4 m in diameter with a water depth of 0.75 m. the inflow of water is about 4 l/sec. Maximum stocking rates of around 25-50 kg/m3in tanks where the water is changed every 1-2 hour. By using aeration this could be as high as 150 kg/m³.The fish in tank culture are fed complete feed, usually 30-35% crude protein for fish over 50 g average weight. 

 

 Floating cages and pens

 

Floating cages:

Cage culture is rearing of fish from juvenile stage to commercial size in a volume of water enclosed on all sides. Cages are floating structures with a net suspended below and are adapted to water areas which cannot be drained. Cages may be square, rectangular or round. Culture of fishes in cage is innovative and novel concept to explore potential of lakes, reservoirs and riverine resource’s.

 

Advantages of cage culture

Ø  Uses existing water bodies.

Ø  Lower capital cost compared with land based farms.

Ø  It has technical simplicity with which farms can be established or expanded.

Ø  Easier stock management and monitoring compared with pond culture.

 

Disadvantages of cage culture

Ø  Stock vulnerable to external water quality problems such as low DO, Algal blooms.

Ø  Stock is more vulnerable to fish eating predators such as water rates and birds.

Ø  Growth rate influenced by ambient water temperature.

 

Pens

 Pen culture is raising of fish in volume of water enclosed on all sides except bottom is. Pens are consider as hybrid between pond and cages. In pens  the bottom of the lakes/ reservoirs forms the bottom of the pens.

 

 

Advantages of pen culture

 Intensive utilisation of available space.

 Easy to harvest.

Ø      The flexibility of size and economy.

Ø      Availability of natural food.

 

Disadvantages of pen culture

Ø                  High DO and water flow

Ø                  Rapid spread of disease

Ø                 Risk of theft

Ø  Conflict with multiple use of natural water

 a) Earthen ponds    

 (b)Raceway

 (c)Concrete tanks                                                   

 (d)Fiberglass tanks

(e)Floating cages        

(f) Pen culture

 

Type of culture structure

 

 (B) Water exchange

 

According to water exchange there are two main systems

 

1.      Static systems

The pond with no exchange of water during the culture period. Static pond culture is usually extensive. The major problems is maintaining water quality. Example of static systems are traditional pond culture

 

2. Open systems

The aquatic organisms are confined / protected within the farm in a substantial amount of water (lake or ocean) so that the water quality is maintained by natural flows and processing. Open system uses the environment as fish farm. There is no artificial circulation of water through or within the system.These are intensive systems. The example of open system is Cage system.

 

3. Closed or re-circulating system

Recirculating systems is attributed by minimal connection with the surrounding environment and the original water source. These systems have minimal exchange of water during a production cycle, so the name ‘closed’ systems.

Advantages of closed systems

 

 Harvesting is easy

 Complete control over water condition

Stocking density is High

 Require minimal water

 Food and drugs can be added efficiently into the system

 

Disadvantages of closed systems

1.     High capital coast

2.     Require very careful management

3.     Rapid spread of disease.

 

C) Intensity of culture

 

1.  Extensive /conventional system:

Extensive aquaculture is least managed form of fish farming i.e. little care is taken. An extensive aquaculture system involves large ponds measuring 1 to 5 ha in area with stocking density limited to <5000 fishes /ha. No supplement feed is given therefore, has limited inputs to maintain fish growth and survival. Noaeration and fertilization. Yield is poor 500kg-2 tonn/hac. Labour and investment costs are low and this system results in minimum income.

 

2.  Intensive system:

High intensity aquaculture yields 15-100ton/hac or more. The stocking rate is much higher 10-50fish/m3. It is well managed form of fish farming. Fish are fed with complete diets (protein rich diets).  BMP is undertaken to maintain optimum water quality parameters.

Intensive systems may be in:

•      ponds {shrimp ( tropical /subtropical regions)}

•      Raceways {trout species (temperate regions)}

 

(D) Fish farming methods

 

1.  Monoculture

Monoculture is a fish production system in which one species is reared in culture system. Monoculture of high value and market oriented fish in intensive system is common practice. The major fish species cultivated in monoculture are trout, tilapia, carpetc.

 

2.      Polyculture

Polyculture is a fish production system in which two or more different fish species are farmed. Species successfully stocked together are differ in their feeding habits and occupy different trophic niches in the pond. Common fish species in India polyculture are catla, rohu, mrigal, silver carp, grass carp and common carps and this system is sometimes also called as composite fish culture, Polyculture of common carp with all-male tilapia, and sometimes also with silver carp commonly  practiced  in Egypt.

 

 

Recirculatory aquaculture systems (RAS)

 

The key obstacles for further growth ofaquaculture systems are lack of space and new sites (due to competition with other uses and interests), restricted fresh water availability, and concerns over pollution. The Recirculating Aquaculture Systems (RAS) has been encouraged as one of the possible solutions and opportunities to further expansion of aquaculture. It is environmentally friendly way of producing fish at a commercial level.

 The nutrients from the farmed fish can be used as fertilizer on agricultural farming land or for biogas production. Recirculating Aquaculture System may produce up to 500 MT of fish per year in same area.Recirculatory aquaculture circumscribe the system used for the rearing of aquatic animals where 90% or above of water is reconditioned and circulated. It is an intensive land-based aquaculture system carried either in open air or indoors.

 

 

 

RAS COMPONENTS

 

1)      Fish Tanks

The tanks must meet the requirements of fishboth in terms of design andenvironment.5000-10000 liters non-corrosive tank (plastic or fiberglass) are most commonly used.

2)      Mechanical filter

 

Mechanical filter is used to remove the suspended solids from the system. These solids, primarily faecal matter, need to be removed in order to maintain water quality. Variouskinds of rotating screens such a drum filter, disc filter, rotating belt, horizontally disc are used

 

Foam fractioner

Foam fractionation is used to remove and control the build-up of fine suspended solids and dissolved organic solids which cannot be removed by traditional filter.

 

 

3)      Bio filter

The bio filter is a biological process carried out by bacteria.

i)     Heterotrophic bacteriathat oxidise the organic matter by consuming oxygen andproduces CO2, ammonia, and sludge.

ii)   Nitrification which is conducted by nitrifying bacteria, removing ammonia from water byturning it into nitrite and nitrate.

 

Bio filters used in recirculation systems can be designed as

 

i)   Fixed bed filters -the plastic media is fixed and not moving while the water flowsthrough it.

ii)  Moving bed filters - the plastic media is moving around in the water inside the bio filter by a current created by pumping in air.

 

 

4)      Degassing/aeration/stripping

Method of removal of CO2, free Nitrogen and H2S from system water flow which are harmful to fish. In a degasser, the water flows through a distribution plate with holes, and is then flushed down through a fixed bed of plastic media stacked in columns.

 

5)      Oxygenation

In RAS system DO must be monitor and adjusted to saturation level. Aeration can bring the saturation level up to above 90%.

 

7)      Ultraviolet light

UV disinfection is used to destroy DNA in biological organisms. It is used to kill Bacteria, viruses, fungi and small parasites.

8)      Ozone

Ozone is used to destroy unwanted organisms too small to be caught by the mechanical filters. In ozone treatment technology micro particles are broken down into molecular structures that will bind together again and form larger particles so the microscopic suspended solids too small to be caught can be removed from the system. This technology is referred as water polishing.

 

SPECIES SUITABLE FOR RAS

Arctic char (Salvelinus alpinus), Atlantic salmon, smolt (Salmo salar), Eel (Anguilla anguilla), Grouper (Epinephelus spp.), Barramundi/ Asian Seabass/Bhetki (Lates calcarifer), European Seabass/ Seabream (Dicentrarchus labrax / Sparus aurata), Sturgeon (Acipenser spp.), Turbot (Scophthalmus maximus), Whiteleg Shrimp (Penaeus vannamei), Yellowtail Amberjack (Seriola lalandi), Cobia (Rachycentron canadum),  Silver/Indian Pompano (Trichinotus Blochii/ Trichinotus mookalee), Tilapia (Oreochromis niloticus), Pearl spot/Karimeen (Etroplus suratensis), Pangasius (Pangasianodon hypophthalmus), Rainbow Trout (Oncorhynchus mykiss), especially in Hilly/cold water Region.

 

Advantages of RAS

 

Bio-secure:

Closed indoor facility, Very low water requirement, Entry and exit of

 

Pathogensis restricted Economy:

Less cost than water exchange system Predictable/Low risk: Constant water parameters (no water exchange), hence less stress to animals, Protected from external entry of pathogens, Isolated from weather related water quality fluctuations.

 

Antibiotic free:

Bacterial load under control due to following factors, higher level of Biosecurity, Reduced levels of suspended solids, Low stress condition, low Ammonia/nitrite, constant DO/Ph/Alkalinity/Temperature, Use of Probiotics, Ozone

 

Eco-friendly: Zero usage of hazardous chemicals, Very low water discharge, lower power consumption, lesser space required due to higher densities, Release of pathogens into the environment controlled due to better biosecurity.

 

Disadvantages

Ø  Constant uninterrupted power supply is required if electric power fails than backup of electricity is required.

Ø  Capital cost of starting a recirculating aquaculture system is high as compared to ponds and raceways.

Ø  Good water source is required preferably borehole

Ø Good fish feed quality, preferably high protein and fat extruded diets with high digestibility

Ø  Technically skilled staff able to work in a medium tech environment

 

Application of aquaculture in food production

Food security is the principal path for development of the socioeconomic status in any country in the world to overcome malnutrition. 

The present scenario suggest that under developed countries are still facing problem of malnutrition. 

The human nutrition deficiencies thus focus on the importance of animal protein in their regular diet. Fisheries plays a significant role in overcoming this problem. Thefishes are the highly nutritious and cheapest protein sources, and a valuable supplement in diets by providing essential vitamins, proteins, micronutrients, and minerals, for the economically backward people. 

Aquaculture is playing an essential role in the developing countries for development of national economic and global food supply. 

The aquaculture has the continuous potentiality for developmental goals for the country economy and better human welfare.Fish provides about 16% of the animal protein consumed by humans and are a valuable source of minerals and essential fatty acids.

 Fish is the primary source of omega-3 fatty acids in the human diet.Omega-3 fatty acids are important nutrients for normal brain and eye development of infants, and have preventative roles in a number of human illnesses example cardiovascular disease, lupus, depression, and other mental illnesses. Asia predominates both capture fisheries and aquaculture production, whereas India is second largest aquaculture producer in world. 

The present fish production of India is 13.42 mmt out of which inland share is 65 %( 9.71mmt) and marine share is 35 %( 3.71mmt).Indian aquaculture is dominated by major carps which accounts for 80%. 

 

Aquaculture vs Agriculture

Aquaculture is the cultivation of aquatic products such as aquatic plants, fish and other aquatic organisms especially for human consumption. Agriculture is the cultivation of the Plants and their harvesting, and the rearing, management and husbandry of livestock.

 

Main Findings 

       Types of aquaculture systems pdf

 

Types of aquaculture systems ppt

 

Types of aquaculture pdf

 

Intensive aquaculture system

 

Types of fish culture system

 

Methods of aquaculture

 

Types of ponds for fish

 Credit of Writing goes :

Aatira Farooq, M.FSC first year division aquaculture, CIFE Mumbai and Dr. Mohd Ashraf Rather, Assistant Professor, SKUAST-K